His full name, "Tom Cat", is based on "tomcat", a phrase which refers to male cats. He is very rarely heard speaking with the exception of a few cartoons (such as 1943's "The Lonesome Mouse" and Tom & Jerry Tales' League of Cats) and "Tom and Jerry: The Movie". His only notable vocal sounds outside of this are his various screams whenever he is subject to pain or panic. He is continuously after Jerry Mouse, for whom he sets traps, many of which backfire and cause damage to him rather than Jerry. His trademark scream was provided by creator William Hanna.

Tom has changed remarkably over the years upon his evolution, especially after the first episodes. For example, in his debut, he was quadrupedal and had normal cat intelligence. However, over the years (since the episode Dog Trouble), he has become almost completely bipedal and has human intelligence and he is similar to his previous appearance, in 1945 shorts he had twisted whiskers and his appearance kept changing. In the 1940s and early 1950s, he had white fur between his eyes. In newer cartoons, the white fur is gone. As a slapstick cartoon character, Tom has a superhuman level of elasticity. Tom is usually defeated (or very rarely, killed, like in Mouse Trouble, where he explodes) in the end, although there are some stories where he outwits and defeats Jerry.

Besides Jerry, Tom is shown to have rivalries with some characters depending on the cartoon. One example is a black alley cat named Butch. He is shown as Tom's rival for most cartoons he's in. In the cartoon Springtime for Thomas, Jerry wrote a letter and tricked Butch into thinking it was from Toodles Galore in an attempt to get revenge on Tom. The most frequent rival of Tom is a Bulldog named Spike. This is so because Spike would protect his son Tyke. Jerry would do his best to get Tom in trouble (e.g. dirty Tyke). However in one cartoon, Tom does something that benefits Spike. Other rivals include a yellow canary named Cuckoo, a duckling named Quacker, and many others.

Despite almost never speaking, Tom's personality is almost always shown. He is usually a depicted as a fun-loving character, who is kind to anyone, except for Jerry. When angered by him, Tom goes onto full attack mode, chasing after him. Other times he can be scared easily and usually hides in spot when this happens. His rival, a black alley cat named Butch is often shown as an antagonist to Tom; the alley cat often makes fun of the title character or rivals him over his love interest Toodles Galore. In some shorts, he shown as a friend to Tom.

Shorts featuring Spike the Bulldog are a different story, however. These cartoons have a basic plot pattern: While Spike is in the middle of doing something, such as sleeping or building a doghouse, Tom always ends up ruining it, causing Spike to get angry and do something horrible to him. This becomes more evident when Spike's son Tyke was introduced. In these shorts, Spike is usually teaching Tyke how to be dog or just hanging out with him. But, Tom would be chasing Jerry as usual. Jerry would often do his best to get Tom in trouble; he usually succeeds and the cat would beat up by Spike.

In most of Tom's appearances, he had very little dialogue. In the early 1940s shorts, Clarence Nash provided the hisses, meows, and screeches for the character. After 1942, Tom and Jerry co-creator William Hanna provided the gasps, screams, yells, and laughs until the demise of the MGM Cartoon Studio in 1957. In between this time period, Harry E. Lang, Billy Bletcher, and Daws Butler provided vocal sounds for Tom. In Mouse Cleaning (1948), actor Stepin Fetchit voiced him in a sequence in the cartoon.

In 1961, when Rembrandt Films took over the production of the series, voice actor Allen Swift voiced Tom for most of this era, until a year later in 1962. The next year,